• UFRJ Nautilus

Diving into the unknown: meet the Drone project

Updated: May 12

The UFRJ Nautilus, since its creation, has been marked by its projects in the field of autonomous underwater vehicles - the well-known AUVs, steadily approached by previous posts -, which started a little over 5 years ago. During this period, lots of experience and international recognition were gained. Not only because of team growth, but also because of a craving for knowledge, for producing useful technologies and, especially, for diversifying its occupation area, Nautilus, at this moment, is diving into a new and challenging space: the drone.

It is essential to emphasize, beforehand, that the drone is not the main project of the team at this stage because there is a work in progress in the AUV called “Lua” (“Moon” in portuguese).

What does the drone consist of?

The drones theme is not brand new in this website: this same matter had already been approached by “Flying Robots and Swimming Robots: drones and AUVs”. In that post, you were introduced to the concept of UAV (Unmanned Aerial Vehicle) and, besides, you learned a little bit about the history of drones and about the operation of some parts, like the battery, the structure and the control system.

Briefly recalling, drones are unmanned aerial vehicles which aim to achieve a stipulated function, for instance: looking for flaws in storage tanks, in oil platforms and in ships, as aforementioned in the post. The usage of these vehicles, for several reasons, is expanding exponentially with the passage of time. A famous example can be noticed in the image below, withdrawn from the Opening Ceremony of Tokyo Olympics of 2021.

Globo Terrestre iluminado por drones

Now, in this post, the objective is to dive a little deeper in the theme, evidencing the group’s intention to inform, as much as possible, you about what is going on internally, and introduce to you about our drone project in specific, revealing its purposes and its first model. It is important to point out that the mechanical aspects of the project will be our last discussion topic in this article.

Our area of development: description of geological aspects

As aforementioned, there is a substantial number of possible applications for flying robots and, that is why, there was an initial divergence in the team over the decision on the project development topic. The suggested topics were:

  • Flooded areas - location of floods and inundations;

  • Impacted areas by the desertification - location;

  • Mapping - description of geological aspects of an area looking forward to planning urban occupation;

  • Calibration with satellite sensors - bridge between the micro and the macro/validation of satellite information.

In relation to the first two topics, which refer to a spatial analysis of risk situations, it is correct to assert that this technology is already being softly applied in Brazil. The usage of these types of drones is extremely important in order to obtain data that was thought to be imperceptible and to identify possibly hazardful situations. Therefore, professionals like biologists and environmental engineers can elaborate, in an efficient manner, a planning of environmental management related to an ideal of preservation, sustainability and economic profitability.

As commented, this technology is already being applied here in the national territory and an example of a company that uses this innovation is the CPRM. Also known as Geological Service of Brazil, CPRM is a public company vinculated to the Mines and Energy Ministry of Brazil (MME). This company provides, through its official website, the SACE - Critical Events of Alert System - service, which offers information about several rivers across the country, like the Amazon Basin and the Xingu River Basin. Right below, the company drone can be observed so as the SACE emitted on 08/24/2021 at 18:39.

Another application thought for the Nautilus drone consisted in calibration with satellite sensors. It is accurate to affirm that the satellites are widely used in the current days: not only for GPS, but also for remote sensing, a technique which has been largely amplified due to technological advancements in the field. For remote sensing, particularly, it is extremely valuable the usage of a UAV to validate the information acquired by the satellite.

Consequently, the drone, with this application, would have a high relevance for the satellite because it would capture the images in a crispier way, in the form of mosaics. The drone would be a fundamental piece of the process by its bigger capacity - when compared to the satellite - of pattern recognition. The next figure illustrates the explained procedure.

Finally, this article has come to its most important item to be approached: mapping of geological aspects of an area planning an urban occupation. This purpose, as it is said in the subtitle, was chosen to be developed by the competent Nautilus team.

The drones for mapping do not differ a lot from the others discussed, especially considering structural and technological elements. However, mapping drones do differ when it comes to purpose: the Nautilus drone will have the importance of providing, for the designers of the area, the urban plot of the location. Urban plot is a geographical concept related to the topography of a place, that is, how the elevation of the locations is distributed by the region in relation to the sea level. This is a crucial information for the disposition of the constructions in the city, always looking forward to the best use of the territory.

Furthermore, the drone can also help in the urban management of a city, allowing it to visualize possible improvement points. The image below illustrates the explanation:

“Yes” to aerodynamics, but also “yes” to aesthetics

With the function already defined, it was left for the Nautilus Mechanics team to imagine and present possible models of the drone’s body. The designs were made considering technical aspects, like aerodynamicity and materials availability, elegance and style.

Referring to the technical matter, aerodynamic modeling is all about the robot’s capacity to endure the effects of air resistance and, that is why, it is a crucial stage of the drone’s efficiency. There is no meaning in having the most powerful battery or the most perfect algorithms if the body is not designed to yield everything it can. Therefore, we elaborated a drone in which its gravity center (GC) - that is, the resulting point of weight force - match its center of pressure (CP) - that is, the resulting point of air resistance forces. In order to obtain this outcome, the object must present a symmetrical modeling, like the image below:

Solidworks 2020

From that image, it is extremely meaningful to point out that the 6 illustrated arms are modular, which means that they can easily be detached and refitted. This parameter must be considered at the very beginning of the structure drafting of the project because it is important for the portability capacity of the drone.

In relation to the materials, the PPS polymer (Polyphenylene sulfide) is the most reliable option to be the main parcel of the drone’s body. Besides its powerless humidity absorption and its immense chemical resistance, the polymer owns an elevated operation system in high temperatures and great parameters of mechanical resistance, the most essential property of structural materials.

Lastly, in addition to all those discussed issues, the semblance factor was treated with high relevance because a good looking drone is attractive for sponsors and adds value to the team, in general. Nautilus owns the “looks” of what it gives to the world and, if its products do satisfy the team in a proud way, it means that Nautilus has succeeded in its mission. Therefore, the appearance of the drone must match the group’s ideas: in other words, the drone must be an authentic portrayal of Nautilus' identity.

Written by Bruno Ignez


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